Lake Superior Perhaps Affected by Climate Change

Stretching across this image is Lake Superior, the largest of the five traditionally-demarcated Great Lakes of North America. Visible to its north, in the upper right corner, is the frozen Lake Nipigon.

Despite being the largest freshwater lake in the world by surface area, and the world’s third-largest freshwater lake by volume (it is deep enough to hold the combined water in all the other Great Lakes), over the last five years scientists have reported that Lake Superior is losing water and getting warmer. The changes to the lake could be signs of climate change, although scientists aren’t sure.

Superior’s level is at its lowest point in eight decades, and the average water temperature has surged 4.5 degrees since 1979, significantly above the 2.7-degree rise in the region’s air temperature during the same period.

Water levels also have receded on the other Great Lakes since the late 1990s. But the suddenness and severity of Superior’s changes worry many in the region. Shorelines are dozens of yards wider than usual, giving sunbathers wider beaches but also exposing mucky bottomlands and rotting vegetation.